1. Field of the Invention
The present invention relates to a feed additive composition for ruminants, for example, a feed additive composition for ruminants which is capable of bypassing a rumen in lactating cows, and a method of producing the same.
2. Discussion of the Background
When ruminants ingest feed, a portion of the nutrients in the feed is exploited as a nutrient source for microorganisms living in the first stomach (i.e., rumen). Therefore, there have been used feed additive preparations for ruminants in which nutrients in the preparations are protected with protective agents that are not degradable by microorganisms in rumen so that the nutrients are not exploited by microorganisms while they pass through the rumen.
The main nutrients used to supplement feed for ruminants are amino acids. The solubility of amino acids varies with the type of amino acid, and according to “Handbook of Amino Acids,” published by Kogyo Chosakai Publishing Co., Ltd. 2003, the solubilities (g/dl) in water at 0° C., 20° C., 40° C., and 50° C. for L-lysine monohydrochloride, which is one of the basic amino acids, are 53.6, (67.0), 95.5, and 111.5, respectively; for L-methionine are 3.0, 4.8, (6.5), and 7.3, respectively; and for L-isoleucine are 3.8, (4.0), (4.5), and 4.8, respectively (the values in parentheses are values extrapolated from solubility curves). As is clearly shown from these values, although L-methionine has low solubility in water, L-lysine monohydrochloride is very soluble in water (the solubility is several tens-fold the solubility of L-methionine), and thus is easily eluted from a preparation to rumen juice. Therefore, it is an especially important issue to prevent elution of basic amino acids, particularly L-lysine monohydrochloride which is generally used in the form of a hydrochloride, to the rumen juice, and exploitation thereof by microorganisms.
As one of the feed additive preparations for ruminants in which nutrients are protected with protective agents, there is a dispersion-type preparation in which the nutrients and protective agents are kneaded together. However, in the case of dispersion-type preparations, amino acids are partially exposed at the preparation surface, and thus when the amino acids are in contact with the rumen juice of pH 6 to 8, the amino acids are prone to be eluted. Therefore, it is difficult to say that prevention of the loss of amino acids in the rumen, particularly basic amino acids, is sufficiently accomplished. Furthermore, formulation is carried out using a variety of protective agents so as to reduce the loss of amino acids from the preparations, and as a result, a problem arises that the content of amino acids in the preparations decreases. Thus, in general, it is difficult to produce dispersion-type preparations containing amino acids in an amount exceeding 40% by weight. Further, in order to prevent the loss of amino acids in a dispersion-type preparation, there have been developed coated type preparations formed by using the dispersion-type preparation as a core, and further coating the core with a coating agent to encapsulate the dispersion-type preparation. In this preparation, since there is no chance for the amino acids to be exposed at the preparation surface due to the coating, the amino acids are relatively stable in the rumen juice, but such type of preparations have a drawback in terms of production, such that the production process is complicated compared to the production process of dispersed type preparations, and thus more processes are needed.
JP-B-49-45224 describes the production of dispersion-type granules having a size of several millimeters or less, using a mixture of oils and fats having a melting point of 40° C. or higher and oils and fats having a melting point of 40° C. or lower as a protective agent, by dispersing amino acids or peptides in the mixture, and injecting the mixture into water of 20° C. to 40° C. through nozzles having a diameter of 0.8 to several millimeters. JP-B-49-45224 also describes the production of granules containing 30 to 40% of L-methionine or L-isoleucine as the amino acid, which both have low solubility in water; however, there is no description of the production of granules containing L-lysine monohydrochloride, which has high solubility in water.
JP-A-2005-312380 describes a method of producing a dispersion-type rumen bypassing agent by solidifying a mixture containing hydrogenated (hardened) oil, lecithin, and saturated or unsaturated fatty acid monocarboxylates having 12 to 22 carbon atoms, as protective agents into spheres having a diameter of 0.5 to 3 mm, by an air spraying method which sprays the mixture into air at a liquefaction temperature of the protective agents, which is from 50 to 90° C. JP-A-2005-312380 also describes that a rumen bypassing agent containing 40.0% by weight of L-lysine monohydrochloride can be produced by means of the above production method. However, in the production method described in JP-A-2005-312380, it is necessary to use a mixture having low viscosity so as to allow the mixture to pass through the spray nozzles, but on the other hand, if the content of L-lysine monohydrochloride in the mixture exceeds 40% by weight, the molten mixture obtains high viscosity, and thus it is difficult to make the mixture to pass through the spray nozzles. Therefore, a preparation containing L-lysine monohydrochloride at a high content which exceeds 40% by weight cannot be obtained by the above method. In fact, JP-A-2005-312380 does not describe a preparation containing L-lysine monohydrochloride at a high content which exceeds 40% by weight. Furthermore, although the method described in JP-A-2005-312380 has a characteristic feature wherein small spherical granules having a diameter of 3 mm or less with a relatively well established granularity can be obtained, there is a drawback that since the granules are small particles, the granules are likely to escape through dry fodder and be sorted out when mixed with feedstuff.
JP-A-2006-141270 describes that L-lysine monohydrochloride is coated with a coating composition including (A) hydrogenated oil, (B) lecithin and (C) a preservative, and thus a dispersion-type rumen bypassing agent for ruminants containing (C) in an amount of 0.01 to 2.0% by weight was obtained. Furthermore, in Table 1 of JP-A-2006-141270, particles containing 37.5% by weight of L-lysine monohydrochloride are described. However, the method described in JP-A-2006-141270 utilizes the air spraying method which sprays a mixture into air with an extruder as in the case of the method described in JP-A-2005-312380, and therefore, an L-lysine monohydrochloride preparation having a content exceeding 40% by weight cannot be obtained, as discussed in regard to the method described in JP-A-2005-312380. In addition, it is pointed out in Example 1 of JP-A-2006-141270 that a rumen bypassing agent solidified into spheres of 0.5 to 2.0 mm in size was obtained; and it is pointed out in paragraph [0005] of the specification, by citing from JP-A-2000-60440, “since the particle size is as large as 4 to 15 mm, the particles are prone to disintegrate by mastication . . . ” That is, when the particle size is large, the agent is physically destroyed by cow's mastication, and the rumen bypass rate is decreased; and with regard to the coated type preparation, it is pointed out that “ . . . since this rumen bypassing agent is double-coated, there has been a drawback that when the coating at the core surface layer part is destroyed by rumination, mastication or the like, the protective effect is extremely reduced, or the like.”
Meanwhile, JP-A-63-317053 describes a coated type feed additive for ruminants, wherein a core containing a biologically active substance consisting of L-lysine monohydrochloride and other excipients or binders is coated with at least one selected from fatty acid monocarboxylic acids including lecithin and glycerin fatty acid esters, hydrogenated oils, and beeswax/waxes. The content of L-lysine monohydrochloride in the core was 65% by weight, but when the coating layer which occupies 20 to 30% by weight in the final preparation is also included, the content of L-lysine monohydrochloride in the preparation becomes 52 to 39% by weight.
JP-A-5-23114 also describes a coated type feed additive composition for ruminants, wherein cylindrical granules produced by extruding a mixture containing a biologically active substance such as L-lysine monohydrochloride through a screen are rendered to be spherically shaped and used as a core, and this core is coated with a composition including one member selected from aliphatic monocarboxylic acids, hydrogenated oils, beeswax and waxes, and lecithin and an inorganic salt which is stable under neutral conditions and soluble in acidic conditions. It also describes a preparation containing L-lysine monohydrochloride in the core in an amount of 50% by weight.
The above-described coated type preparations are indeed advantageous in view of containing large amounts of biologically active ingredients, however, since their production includes first making a core containing a biologically active ingredient, and further coating this core with a coating agent, the production is achieved not in a continuous mode but in a batch mode, therefore, an increase in the number of production processes is unavoidable. Furthermore, in the invention described in JP-A-5-23114, when the biologically active substance is exposed at the surface by the grinding or damage due to mastication of lactating cows, the resistance to degradation in rumen juice is reduced, and in order to avoid such reduction, the particle size is controlled to be several mm or less, or to 3 mm or less. However, there may be posed a problem such that a preparation having such a dimension is sorted out when mixed with the feedstuff.